Process of binding the active material of positive-pole lead electrodes.



UNITED STATES PATENT oEEIoE.

WILLIAM MORRISON, OF DES MOINES, IOWA.

PROCESS OF BINDING THE ACTIVE MATERIAL 0F POSITIVE-POLE LEAD ELECTRODES.

No Drawing.

To all whom it may concern:

Be it known that I, \VILL'LAM hIoRuIsoN, a citizen of the United States, residing at Des Moines, in the'county of Polk and State of Iowa, have invented certain new and useful Improvements in Processes of Binding the Active Material of Positive-Pole Lead Electrodes, ofwhich the following is a specifica'tion. v This invention relates to the production ofa permanent and insoluble binder for the which have these characteristics are tong-- sten, taiitaluni and niobium, otherwise called columbium.

To illustrate the invention, there will be described a process of producing a leadperoxid electrode employing a compound of tungsten as the binder. For this purpose, a metallic support, for example a grid of antimonial lead, is pastedor filled with the usual mixture of minium, litharge and a sulfuric acid solution, in which mixture lead sulfate forms as a provisional binder. Complete formation, or peroxidation, of the-active material is then preferably initially effected by placing the pasted grids, alternately with unfilled grids servingas dummy electrodes of the opposite polarity, in a sulfuric acid solution having a specific gravity of 1.200

to 1.250 and passing an electric current through the solution, alternately in opposite directions, until the paste has been sufliciently expanded, care being taken not to force the discharge beyond the normal in-v tended capacity of the electrodes. Sodium paratungstate is now dissolved in a. tenvolumc aqueous solution of hydrogen peroxid, that is to say a solution capable of liberating ten volumes of oxygen, and there is then added slowly and with constant stirring a sulfuric acid solution having a spe cific gravity of 1.200 to 1.225 until efi'ervescence ceases. There is then added an addi- Specification of Letters Patent. Application filed February 23, 1912.. Serial No. 679,300.

Patented Apr. 2, 1912.

posure to air, and again clipped and dried one or more times as may be desired.

One effect of the hydrogen peroxid as above used is to prevent precipitation of tungstio acid upon the addition of the sulfuric acid; and if any tendency to such precipitation is observed, more hydrogen peroxid should be added until the solution remains clear. The hydrogen peroxid is used in some excess, and serves also in the presence of the sulfuric acid to reduce the lead peroxid of the formed electrode, and thereby to facilitate the ultimate production of the leadtungstenoxygen binder. If stronger hydrogen peroxid solutions are used a correspondingly smaller volume will be required. The positive-pole electrode should then receive a prolonged and strong charging treatment in sulfuric acid, with dummy negatives, before assembling in the battery,

in order to remove or to render insoluble any remaining solublecomponents of the plate.

The tungsten-oxygen compound appears to play the same role in the binder compound as does the sulfur-oxygen compound in the ordinary lead electrodes in which lead sulfate constitutes the binder. The leadtungsten-oxygen compound is however, as compared with the lead sulfate heretofore commonly used as a binder, very permanent and insoluble, being chemically and electrochemically inert; under the conditions of use, while acting as an efficient binder. This binder, by reason of its inactivity, somewhat decreases the capacity of the electrodes, to the same extent that it displaces or occupies the place of lead .peroxid.

- The initial formation of the electrodes may be omitted and the filled grids may be at once placed in the tungstate solution to im: pregnate the active material with the inder, formation being subsequently effected. Such subsequent formation, however, consumes a much larger amount current than does initial formation.

Positive-pole electrodes having a binder containing tantalum or niobium may be prepared by the method above described, a soluble tantalate or niobate, as for example potassium hexa-tantalate or niobate, being substituted for the sodium paratungstate.

The active material of Plant electrodes,

formed out of solid lead, may also be bound by dipping them in a hydrogen peroxid solution of a salt of the binder-metal, and then completing the treatment as before.

I claim:

1'. The process of binding the active material of positive-pole lead electrodes, which consists in dissolving in a solution of a reducing agent a compound having in its acidic radical a metal incapable of directlyelectronegative elements, which'can constitute the acidic radical of compounds having lead as abase, adding sulfuric acid, and saturating the active material with the resultant solution. 2. The process of bindin the active material of positive-pole lead e ectrodes, which consists in dissolving in a solution of hydrogen peroxid a compound having its acidic radical a metal incapable of directly replacing hydrogen in a sulfuric acid solution; insoluble byanodic oxidation in a sulfuric acid solution; incapable ofcathodic reduction to metal, or of electrolytic separation as metal, in a sulfuric acid solution; and capable of forming complex anions with electronegative elements, which can constitute the acidic radical of compounds having lead as a base, adding sulfuric acid, and saturating the active material with.the resultant solution.

3. The process of binding the active material of positive-pole lead electrodes, which consists in dissolving in a solution of a reducing agent a compound having tungsten in its acidic radical, adding sulfuric acid, and saturating the active material with the resultant solution.

4. The process of binding the active material of positive-pole lead electrodes, which consists in dissolving in a solution of hydrogen peroxid a compound having tungsten in its acidic radical, adding sulfuric acid, and saturating the active material with the resultant solution.

In testimony whereof I afiix my signature in presence of two witnesses.

EUGENE A. BYRN-ES, N. P. LEONARD.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

' Washington, I). G. 

